According to psychologist Jean Piaget, such skills emerge during the preoperational stage. This is the second stage in his ...

The stage from 18-24 months to 7 years Piaget called preoperational, where children can think about things in symbolic terms. They can pretend, verbalize, and understand past and future.

Being able to represent objects in their mind is another key part of the preoperational stage and, as a result, you might see them taking part in pretend play. Image caption, According to Piaget ...

In Piaget's Three-Mountain Task ... also serves as an important transition between the preoperational and formal operational stages. The growing ability to mentally manipulate information and ...